[iocp] Warn about INFINITE timeout

This should warn about a potential issue to stdout; for the time being
(maybe it should be an 'lcb_assert')? - it's rare behavior but
it's normally a bug in the library

Change-Id: Icaf09f6ffbda1e8004ea04d352d80f82c4c34439
Reviewed-on: http://review.couchbase.org/28189
Reviewed-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>
Tested-by: Sergey Avseyev <sergey.avseyev@gmail.com>